Godot provides built in functionality to make frequent operations
easier. Additionally, Godot’s shader editor will detect errors as you
type, so you can see your edited shaders in real-time. It is also
possible to edit shaders using a visual, node-based graph editor.

Create a new ShaderMaterial in some object of your choice. Go to the
“Material” property and create a ShaderMaterial.

Next, click on the shader material to see its properties. From here you
can create a shader or visual shader. Regular shaders use code to set
their properties while a visual shader uses a node based workflow.

If you need to you can convert a visual shader to a text shader.
However you can’t convert a text shader to a visual shader.

Choose one of them and you can start editing your shader.

If you create a regular shader click on it and the shader editor will open.

If you create a visual shader the visual shader editor will open automatically.

In the visual shader editor you can click a button and see what your visual
shader looks like as shader code. This can be useful if you’re trying to
replicate a text shader as nodes, or it can be used as a preview for converting
your visual shader to a text shader.